Damper blade and assembly



Feb. 2, 1965 F. M. BOOTH ETAL 3,

DAMPER BLADE AND ASSEMBLY Filed June 4, 1962 BY WILL/AM M. KANE 8. L,277%.Zafi.

A 7 TOP/V5 VS United States Patent Ofifice 3,168,028 Patented Feb. 2,1965 3,168,028 DAMPER BLADE AND ASSEMBLY Francis M. Booth and William M.Kane, Marysville, Calif, assignors to Frank M. Booth, Ine, Marysville,Calif., a corporation of California Filed June 4, 1962, Ser. No. 199,9503 Claims. (Cl. 98-110) This invention relates to a damper blade of thegeneral type in which a metal blade includes coaxial shaft extensionssecured thereto and projecting from two opposite edges of the blade forsupporting the blade for rotary 'movement about the axis of saidextensions.

Blades of the above general type have normally been formed with achannel extending across each blade from one of the aforesaid twoopposite edges to the other, which channel opens outwardly of one sideof each blade, and a stub shaft has been positioned within said channelat each of the two opposite ends thereof with each shaft projectingoutwardly of the edge of the blade adjacent thereto. Up

to this point, the present invention employs the same structure.

Heretofore the shafts have each been secured to each blade by use ofcentrally arched metal straps. One strap has been positioned to extendacross each shaft with the shaft projecting laterally into the arch, andthe ends of each strap have been welded to the blade at opposite sidesof the channel that is in the damper blade. strap is drilled to providean opening through the arch Each thereof, and each opening so drilled istapped for a screw. After each shaft has been positioned in the ends ofthe channel between the latter and the arch in each strap, a I set screwis threadedly extended through the tapped opening in said arch and intoengagement with the shaft. In some instances a single shaft may be inthe blade channel projecting at its ends from two opposite edges of thedamper blade, but the same set screw and strap structure is used tosecure the shaft to the blade.

Thus, by the method and structure heretofore employed, six separatesteps are required to secure each of two stub shafts to a damper, andthe straps, screws and welding vibration and noise in some instances,and the fact that the screws project from the blade also subjects themto being injured, as well as frequently causing injury to workmeninstalling the blades, since these screws have relatively sharp edges.

One of the objects of the invention is the provision of a blade andshaft assembly that overcomes the above men- ,tioned objections to theconventional blade and shaft assemblies.

One of the objects of the present invention is the provision of a shaftmounting for a damper blade that is stamped and cut as an integral partof each blade.

Another object of the invention is the provision of a shaft mounting fora damper blade that is formed to frictionally hold each shaft rigid withthe blade at substantially uniform tightness far exceeding any strainthat may be placed on the blade when each blade is in normal use.

A still further object of the invention is the provision of a shaftmounting for securing blade supporting shafts to damper blades, that isformed to preclude interference with the smooth flow of air acrosseither of the two opposite sides of each blade.

Other objects and advantages will appear in the description anddrawings.

In the drawings,

FIG. 1 is an isometric view of a typical installation of damper blades.

FIG. 2 is an enlarged elevational view of one end of a damper bladeshowing the shaft mounting and a shaft, as seen from one side of theblade.

FIG. 3 is an end elevational view of the portion shown in FIG. 2.

FIG. 4 is a cross sectional view taken along line 44 of FIG. 2.

FIG. 5 is a cross sectional view of the blade taken along line 5-5 ofFIG. 2, a shaft being shown in elevation.

FIG. 6 is a semidiagrammatic perspective view illustrative of a methodof forming the shaft securing portion of the blade.

Referring to FIG. 1 -a fire damper is illustrated in which a pluralityof corresponding damper blades, generally designated 1, are supported inparallel side by side relation in a row. Coaxial stub shafts 2 aresecured to each blade 1 at opposite ends thereof, which shafts projectoppositely outwardly of each blade at said ends, and the projecting endsof the shafts 2 are rotatably supported in bearings carried by sideframe members 3 that may support the blades in air ducts or whereverdesired.

The blades of each assembly, such as illustrated in FIG. I carry arms 4projecting from one of the corresponding sides thereof, and which armsmay, in turn, be pivotally connected with a single link or bar 5 forsimultaneously moving the blades to the desired position within a duct,and a holding rod 6 will hold the blades in said positions against theresistance of spring 7 that tends to move the blades to closed position.A fusible link 8 positioned in the air stream will melt to release theholding rod 6 upon a predetermined elevation in temperature in thestream, whereupon the spring 8 will function to automatically move theblades to closed positions.

The present invention is not concerned with the control means employed,or Whether the damper is a fire, mixing or other damper. However, theassembly illustrated in FIG. 1 emphasizes the importance of a secureconnection between the shafts and the damper blades, and also thealignment of the shafts on each blade so that the shafts will turnfreely in the bearings.

The present invention is particularly concerned with the means on theblades for mounting the shafts that support the blades for rotationabout the axis of the shafts 2, and also the blade-shaft assembly.

Insofar as the method of making the blades, and the blade-shaftassemblies are concerned, each blade illustrated in FIG. 1 is oblong inoutline and is formed with a channel 9 extending longitudinally from endto end thereof intermediate the longitudinally extending edges of theblade. This channel will function to reinforce the blade againsttransverse bowing, and also provides a seat for the shafts.

In FIG. 6 one end portion of a blade 1 is positioned over a diegenerally designated 10 that includes a pair of axially spaced elongateddie elements 12 rigidly supported on similarly spaced die blocks 13that, in turn, are held in properly spaced relation on a base plate 14.The adjacent ends of said elements 12 terminate approximately even withthe adjacent sides of the die blocks.

An end portion of the blade 1 is adapted to be positioned, with thechannel 9 opening downwardly, over the die with elements 12 seatedwithin the channel 9. The cross sectional contours of the elements 12where they are received in channel 9 are substantially complementary tothe inner surfaces of the channel 9.

A hold-down member generally designated 15 may include a verticallyreciprocable plate 11 carrying a pair of channels adapted to receive theconvex side of the channel 9 when the latter is in'a position receivingthe die elements 12, as seen in FIG. 6. Plate 11 is rigid with theblocks and is formed with a central opening 17 through which avertically reciprocable punch 18 is adapted to move. This punch elementhas a lower edge that extends longitudinally of elements 12 and thepunch element is adapted to move downwardly between elements 12 to shearthe walls of channel 9 to the planar blade portions extending outwardlytherefrom, along spaced lines .25 (FIG. 2) to a position projecting tothe side of the blade opposite to the remainders of the channel walls,whereby the portion 19 will form an elongated bridge piece extendingbetween the pair of cuts that are at the ends of the portion 19.

The parts 20 of blade 1 at opposite sides of the portion 19, and thatintegrally connect the bridge piece 19 with the blade, willautomatically be drawn out of the plane of the blade to the same sidethereof as the bridge piece, and are a part of the latter. These parts20 have gently curved surfaces leading from the planar surfaces of theblade at substantially less than right angles relative to said planarsurfaces as seen in FIG. 4, so as to function in generally the samemanner as an airfoil, to pass air thereover and past the bridge piece,without causing objectionable turbulence and without causing noise orvibration.

The ends of the bridge piece 19 at points 22 (FIGS. 2, 3, adjacent tothe cuts 25 or the lines of said cuts, are automatically drawn to formconcavely extending surfaces, transversely of the bridge pieces 19, thatare adapted to uniformly and more fully and closely engage a dampermounting shaft 2 than the portion of the bridge piece between the saidportions at points 22, as will later be explained. Y

The lower edge of punch 18 may be slightly curved, in transverse, crosssectional contour, so as not to score the metal of the portion 19' andso that the metal of portion 19 will have a concave contour facing theplane of, the blade, and which is opposite to the contour of the channel9 in the remainder of the blade. a

The distance, at a right angle to the planeof blade 1, between thebottom wall of channel 9 that extends away from the bridge piece 19, andthe concave surfaces of the bridge piece that face the plane of theblade, is such that the shaft 2 must be forcibly pressed or driven intochannel 9 and across the gap between the cuts 25.

FIG. 1 shows shaft 2 at each end of each blade 1, while FIGS. 2-5 alsoshow the shaft in position at one of the ends of a blade. The structureat opposite ends of each blade is identical.

Each shaft 2 has been forced longitudinally thereof to a position inwhich the shaft extends into the channel 9 at opposite ends of thebridge piece and across the gap that is formed by each pair of cuts 25.The portions 21 of the bridge piece at opposite ends thereof mosttightly engage one of the sides of shaft 2 with substantially uni formpressure while the channel walls at opposite ends of the bridge piece,and outwardly of said ends, will engage the opposite sides of the shaftwith similar pressure.

The bridge piece is stamped to one side of the plane of the blade such adistance that it will cooperate with the channel walls engaging theshaft at the ends of the bridge piece, to frictionally hold the shaftagainst rotary movement relative to the damper blade and against axialor pulling movement under any conditions that may be encountered inactual installations. In actual practice, where standard 95 shafts areused, and the walls of channel 9 are formed for such shaft, the mountingsocket that comprises a bridge piece 19 and the channel walls at the endthereof are so designed to rigidly retain each shaft in each such socketagainst axial movement of each shaft relative to the blade at over afour hundred pound pull, and to rigidly hold each shaft against rotarymovement relative to the blade at over seventeen inch pounds torque.

The shafts 2 may obviously be simultaneously fitted on each blade, andboth bridge pieces may be simultaneously formed. The die and punch ofFIG. 6 are not intended to show all elements that may be used, since theholddown plate, for example, may be yieldably held against the blade bysprings, and conventional means may be employed to mount the die, punchand hold-down structure in a punch press.

It should also be noted that parts 23 of bridge piece 19 connect withthe sloping portions extending away from the blade in a direction thatextends toward the axis of the shaft, which insures a more secureengagement-between the bridge piece 19 and the shaft, irrespective ofvariations in the temperature of the air or'gas passing over the blades,and this depression of the bridge piece between portions 20 does notcreate any objectionable turbulence in the air stream.

It is to be understood that the claims appended hereto are intended tocover all changes'and modifications of the example of the inventionherein chosen for the purpose of disclosure which do not constitutedepartures from the spirit of the invention and the scope of the claims.

'We claim:

1. In an elongated sheet metal damper blade formed with a channelextending longitudinally thereof having walls of uniform substantiallysemi-cylindrical cross-sec tional contour from end to end thereofprojecting to one side of said blade providing a concave substantiallysemicylindrical inner surface adapted to follow and engage theoutersurface of a shaft having approximately the same cylindricalcontour, said blade having planar por= tions respectively at oppositesides of said channel, and said channel being open'at the ends of saidblade:

(a) the walls of said channel being formed at a point intermediate theends of the latter with a gap of sub stantial width longitudinally ofsaid channels;

(b) a bridge piece integral with and stamped from Said blade extendinglongitudinally of said channel and across said gap and projecting to theo posite side of said blade that is opposite to said one side thereof;

(c) said bridge piece including side portions of similar size extendinggenerally toward each other from the planar portions at opposite sidesof said channel at angles relative to said planar portions that arerespectively substantially less than a right angle, and

(d) said bridge piece further including an intermediate portion integralwith and connected with said side portions at the ends of the latterthat are remote from said planar portions, said intermediate portionbeing formed with an inner surface of cylindrical crosssectional contourat each of the ends of said intermediate portion axially of the channeland said last mentioned surfaces being concentric with and spaced fromthe axis about which said semi-cylindrical sur-- face of said channel isdeveloped a distance sufricient to coact with said semi-cylindricalsurface that is at opposite sides of said gap for tightly gripping theouter cylindrical surface of such shaft upon driving suchshaft into saidchannel longitudinally of the latter, and I a (e) a cylindrical shaft insaid channel having its outer cylindrical surface tightly gripped bysaid semi-cylindrical surface of the walls of said channel and thecylindrical surface of said intermediate portion of said bridge pieceagainst axial and rotary movement of said shaft relative to saidbladeunder forces substantiallyexceeding those encountered in normal andcontinued operation of said damper blade,

(f) said shaft extending axially outwardly of said channel to provide afree end for mounting in a bearing.

2. In a damper blade as defined in claim 1:

(g) said intermediate portion being in a position closer to said axisabout which said semi-cylindrica1 surfaces are developed than the saidouter ends of said side portions, and

(h) extensions integral with said side portions at their said outer endsextending generally toward said axis integral with and supporting saidintermediate portion in said position.

3. In an elongated sheet metal damper blade formed with a channelextending longitudinally thereof having walls of uniform substantiallysemi-cylindrical cross-sectional contour from end to end thereofprojecting to one side of said blade providing a concave substantiallysemicylindrical inner surface adapted to follow and engage the outersurface of a shaft having approximately the same cylindrical contour,said blade having planar portions respectively at opposite sides of saidchannel, and said channel being open at the ends of said blade:

(at) the walls of said channel being formed with a pair of gapsrespectively adjacent to but spaced from the ends of said blade, saidgaps being of substantial width longitudinally of said channel;

(b) a pair of corresponding bridge pieces integral with and stamped fromsaid blade extending longitudinally of said channel and across said gapsrespectively, and projecting to the opposite side of said blade that isopposite to said one side thereof;

(c) said bridge pieces including side portions of similar size extendingangularly relative to said planar portions to said opposite side of saidblade, each extending from each planar portion with which it isconnected at substantially less than a right angle, and from pointssubstantially equally spaced outwardly of the respective sides of saidchannel a substantial distance;

(d) said bridge portions each further including an intermediate portionintegral with said side portions respectively formed with inner surfacesof cylindrical cross-sectional contour concentric with and spaced fromthe axis about which the semi-cylindrical surface of said channel isdeveloped distances sufficient to coact with said semi-cylindricalsurface of said channel at opposite sides of said gap to respectivelytightly and frictionally grip the outer cylindrical surface of suchshaft upon driving a pair of such shafts endwise into said channel ateach of the ends of the latter;

(2) a pair of cylindrical shafts so driven in said channel having theirouter cylindrical surfaces tightly gripped by said semi-cylindricalsurface of said channel and the cylindrical surfaces of saidintermediate portions against axial and rotary movement of said shaftsrelative to said blade under forces substantially exceeding thoseencountered in normal and continued operation of said damper blade;

(f) said shafts extending axially outwardly of said channel at theopposite ends of the latter to provide free cylindrical ends formounting in bearings;

(g) said intermediate portions being in positions spaced from but closerto said axis about which said semicylindrical surface of said channel isdeveloped than the distances of the outer ends of said side portionsthat are remote from said points are spaced from said axis;

(h) extensions of said side portions at their said outer ends extendinggenerally toward said axis integral with and supporting saidintermediate portions in their said positions.

References Cited by the Examiner UNITED STATES PATENTS 1,230,882 6/17Filbey 126-292 1,288,706 12/18 Shanahan et a1. 29-515 1,480,949 1/24Olinger 126-292 1,675,404 7/28 Cohn 126-292 1,734,013 10/29 Jones126-288 2,427,393 9/47 Eckel 29-515 2,572,491 10/51 Keilwitz 126-288ROBERT A. OLEARY, Primary Examiner.

WHITMORE A. WILTZ, JAMES W. WESTHAVER,

Examiners.

1. IN AN ELONGATED SHEET METAL DAMPER BLADE FORMED WITH A CHANNELEXTENDING LONGITUDINALLY THEREOF HAVING WALLS OF UNIFORM SUBSTANTIALLYSEMI-CYLINDRICAL CROSS-SECTIONAL CONTOUR FROM END TO END THEREOFPROJECTING TO ONE SIE OF SAID BLADE PROVIDING A CONCAVE SUBSTANTIALLYSEMICYLINDRICAL INNER SURFACE ADAPTED TO FOLLOW AND ENGAGE THE OUTERSURFACE OF A SHAFT HAVING APPROXIMATELY THE SAME CYLINDRICAL CONTOUR,SAID BLADE HAVING PLANAR PORTIONS RESPECTIVELY AT OPPOSITE SIDES OF SAIDCHANNEL, AND SAID CHANNEL BEING OPEN AT THE ENDS OF SAID BLADE: (A) THEWALLS OF SAID CHANNEL BEING FORMED AT A POINT INTERMEDIATE THE ENDS OFTHE LATTER WITH A GAP OF SUBSTANTIAL WIDTH LONGITUDINALLY OF SAIDCHNNELS; (B) A BRIDGE PIECE INTEGRAL WITH AND STAMPED FROM SAID BLADEEXTENDING LONGITUDINALLY OF SAID CHANNEL AND ACROSS SAID GAP ANDPROJECTING TO THE OPPOSITE SIDE OF SAID BLADE THAT IS OPPOSITE TO SAIDONE SIDE THEREOF; (C) BRIDGE PIECE INCLUDING SIDE PORTIONS OF SIMILARSIZE EXTENDING GENERALLY TOWARD EACH OTHER FROM THE PLANAR PORTIONS ATOPPOSITE SIDES OF SAID CHANNEL AT ANGLES RELATIVE TO SAID PLANARPORTIONS THAT ARE RESPECTIVELY SUBSTANTIALLY LESS THAN A RIGHT ANGLE,AND (D) SAID BRIDGE PIECE FURTHER INCLUDING AN INTERMEDIATE POTIONINTEGRAL WITH AND CONNECTED WITH SAID SIDE PORTIONS AT THE ENDS OF THELATTER THAT ARE REMOTE FROM SAID PLANAR PORTIONS, SAID INTERMEDIATEPORTION BEING FORMED IN AN INNER SURFACE OF CYLINDRICAL CROSSSECTIONALCONTOUR AT EACH OF THE ENDS OF SAID INTERMEDIATE PORTION AXIALLY OF THECHANNEL AND SAID LAST MENTIONED SURFACES BEING CONCENTRIC WITH ANDSPACED FROM THE AXIS ABOUT WHICH SAID SEMI-CYLINDRICAL SURFACE OF SAIDCHANNEL IS DEVELOPED A DISTANCE SUFFICIENT TO COACT WITH SAIDSEMI-CYLINDRICAL SURFACE THAT IS AT OPPOSITE SIDES OF SAID GAP FORTIGHTLY GRIPPING THE OUTER CYLINDRICAL SURFACE OF SUCH SHAFT UPONDRIVING SUCH SHAFT INTO SAID CHANNEL LONGITUDINALLY OF THE LATTER, AND(E) A CYLINDRICAL SHAFT IN SAID CHANNEL HAVING ITS OUTER CYLINDRICALSURFACE TIGHTLY GRIPPED BY SAID SEMI-CYLINDRICAL SURFACE OF THE WALLS OFSAID CHANNEL AND THE CYLINDRICAL SURFACE OF SAID INTERMEDIATE PORTION OFSAID BRIDGE PIECE AGAINST AXIAL AND ROTARY MOVEMENT OF SAID SHAFTRELATIVE TO SAID BLADE UNDER FORCES SUBSTANTIALLY EXCEEDING THOSEENCOUNTERED IN NORMAL AND CONTINUED OPERATION OF SAID DAMPER BLADE, (F)SAID SHAFT EXTENDING AXIALLY OUTWARDLY OF SAID CHANNEL TO PROVIDE A FREEEND FOR MOUNTING IN A BEARING.